In recent years, biological catalysts such as microorganisms have been widely used for chemical reactions. For example, it is well known that nitriles compounds can be converted into amide compounds by hydration using a certain strain of the genus Bacillus, Bacteridium, Micrococcus or Brevibacterium (U.S. Pat. No. 4,001,081); Corynebacterium or Nocardia (U.S. Pat. No. 4,248,968); Pseudomonas (U.S. Pat. No. 4,555,487); Rhodococcus or Microbacterium (EP-188,316); or Fusarium (JP-A 64-86889/1989).
All of these microorganisms, however, fall under the category of mesophilic bacteria which cannot grow at a temperature of 55.degree. C. or higher.
In addition, the hydration activity of mesophilic bacteria to convert a nitrile compound into its corresponding amide compound are not stable in the range of temperature of higher than room temperature. For this reason, the production of amide compounds using such mesophilic bacteria is usually conducted at lower temperatures. In this case, cooling facilities are required for keeping the reactor at lower temperatures and high quantity of energy is consumed for the cooling, which lead to a remarkable increase in the production cost.